Green Rock said the re-entry of SAP-1, an old mineral exploration hole, to a depth of 443.4 metres on Monday has produced “positive down-hole conditions and bottom-hole temperatures.”

If the results are as postive as the company hopes, Green Rock will deepen SAP-1 into the crystalline basement to confirm the site’s temperature gradients and rock properties.

The company's first well Blanche-1 in GEL 128 on September 26, which recorded the hottest temperatures drilled to date in granite in Australia outside the Cooper Basin, according to Green Rock.

With drilling also identifying horizontal fracturing in the granites, the company is currently completing geophysical logging at the well.

“Another well will be drilled later closer to Blanche-1 to help identify the optimum well design and location for two deep geothermal wells to be drilled next year,” said managing director Adrian Larking.

“[These wells] will be drilled to a depth of five kilometres to facilitate the establishment of a pilot circulation cell for trial electricity generation.”

SAP-1 was originally drilled in the 1970s to a depth of 1,369 metres in sediments overlying the basement rocks, said Green Rock.

It also claims that Blanche-1 is the third deepest geothermal energy well drilled to date in Australia and is the first geothermal well outside of the more remote Cooper/Eromanga Basins to have intersected the target granite.

The granite forms part of the Burgoyne Batholith, which had been proven in the Company’s geothermal exploration licencss by shallower drilling conducted by WMC - now owned by BHP Billiton.

Green Rock was granted geothermal exploration license (GEL 213) totalling 206 square kilometres to the west of GEL 128. The company said the new GEL contained a thicker sequence of cover sediments than in Blanche-1. It will now test whether these sediments will contribute to even higher temperatures in the underlying basement rocks than encountered in Blanche-1.